1. Field of the Invention
The present invention relates generally to wireless communication systems and, more particularly, to baseband signal processing and resource management.
2. Description of the Related Art
This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present invention, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present invention. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.
In 3rd generation or “3G” standards associated with support for high-speed data transmissions, overhead channels are provided to carry control and quality information. The quality and control information includes a link quality indication, decoding acknowledgement and rate control commands. Specifically, in CDMA2000 standard revision C/D, which is hereby incorporated by reference, a Reverse Link (RL) overhead channel, which is a Reverse Channel Quality Indication Channel (R-CQICH), is utilized to support the high speed Forward Link Packet Data Channel (F-PDCH). The R-CQICH carries information for the Forward Link high rate packet data scheduling and cell switching.
When high-speed data service is provided, a wireless unit continuously transmits Channel Quality Indicator (CQI) reports to the base station. The CQI reports are measurements of the Forward Link (FL) pilot energy at the wireless unit. The CQI report is updated each Power Control Group (PCG), which is a time interval of 1.25 ms. A CQI frame contains 16 PCG time slots and lasts 20 ms.
Further, the 3GPP2 standard provides various configurations for CQICH that may be adjusted in the base station and wireless unit. In the Third Generation Partnership Project 2 (3GPP2) standard, two types of CQI reports are allowed, which are a full report and a differential report. The full report is a 4-bit CQI word that represents the sample of the pilot signal during the current PCG. The differential report is a one bit indicator that represents the change of the current CQI from the previous CQI. The full report utilizes more signal power than the differential report, which is one bit indicator. Accordingly, the 3GPP2 standard specifies that the R-CQICH may be configured to operate in a full mode and/or differential mode. In the full mode, all the PCG slots in a CQI frame carry the full reports. In the differential mode, the full reports are generated at the beginning of a CQI frame and followed by the differential bits. Also, a repetition factor may be set for the R-CQICH to adjust the number of times that a full report is retransmitted in both full and differential mode, which may be 1, 2 or 4, for example. At the beginning of a CQI frame in the differential mode, the number of full reports applied is determined by the repetition factor. Similarly, the number of switching slots may be adjusted to provide a cell switch indication pattern, as well. Thus, each of the system or CQI channel configurations may impact the power consumed to provide the CQI signal and provide different adjustments to improve signal quality.
For example, as is shown in FIGS. 10 and 11, exemplary diagrams are provided that illustrate the relationship of the CQI signal power verses different PCGs. In FIG. 10, a Full Report diagram, which may be referred to by reference numeral 160, depicts the CQI signal power for each of the full reports Fa-Fg over the different PCGs 162a-162v. In this diagram 160, the system configurations for the R-CQICH may include the mode being set to full mode and the repetition factor being set to 2. Accordingly, for the PCGs 162a and 162b, the same full report Fa is issued for each of the PCGs. To reduce the power allocated to the R-CQICH, the system configurations may be adjusted to the mode being in the differential mode and the repetition factor being adjusted to 1, as shown in FIG. 11. In FIG. 11, a Differential Report diagram, which may referred to by reference numeral 166, depicts the CQI signal power for the full report Fi and each of the differential reports Da-Do over the PCGs 168a-168v. In this diagram 166, the system configurations for the R-CQICH may include the mode being set to differential mode and the repetition factor being set to 1. Accordingly, in the first PCG 168a, the full report Fi may be provided at the indicated CQI signal power level 170, while the differential reports Da-Do in the subsequent PCGs 168b-168p may be provided at the indicated CQI signal power level 172. Thus, the system configurations impact the CQI signal power.
Similarly, in FIGS. 12 and 13, exemplary diagrams of the switching slots illustrate the power of the CQI signal verses the PCGs. In FIG. 12, the Full Switching Report diagram, which may referred to by reference numeral 174, depicts the CQI signal power for each full report F1-F12 for each of the PCGs 176a-176v. In this diagram 174, the system configurations for the R-CQICH may be set to full mode and the number of switching slots may be set to 4. Accordingly, the full reports F1-F12 are provided over PCGs 176a-176l, for the PCGs 176m-176p, the switching slots S1-S4 may be allocated to carry the cell switch indication pattern. If the repetition factor is increased to 2, then the number of switching slots utilized to repeat the switching slot information may be increased, while the mode may be set to differential mode to reduce the CQI signal power, as shown in FIG. 13. In FIG. 13, a Differential Switching Report diagram, which may referred to by reference numeral 180, depicts a CQI signal power for each full report F13, the differential reports D1-D6, and the switching slots S5-S7. Accordingly, with the repetition factor set to 2, the switching slots S5-S7 may utilize PCGs 182i-182p. With the mode being set to differential mode, the CQI signal power may be conserved during the PCGs 182c-182h, when the differential reports D1-D6 are provided. Thus, the system configurations influence the CQI signal power.
However, the 3GPP2 standard does not address how to determine the optimized CQI configurations based on different system deployment scenarios. Specifically, the 3GPP2 standard does not provide a mechanism for determining how to dynamically adjust the CQI system or CQI channel configurations based on different system deployment scenarios.